P1419: A SINGLE CENTRE PERSPECTIVE ON PREGNANCY OUTCOMES AND SICKLE CELL COMPLICATIONS IN WOMEN ON HYDROXYCARBAMIDE PERI-CONCEPTION.
Authors: Maria Gregori, Kate Gardner, Rachel Kesse-Adu, Nita Prasannan, Eugene Oteng-Ntim
Journal: HemaSphere (2023)

Topic: 26. Sickle cell disease Background: Sickle cell disease (SCD) in pregnancy is associated with high risk of morbidity and mortality. Obstetric complications include preterm delivery, low birth weight, stillbirth and pre-eclampsia. Women also experience increased frequency of vaso-occlusive crisis (VOC), infection, blood transfusion and critical care admission. Prior to pregnancy, many patients with a severe phenotype of SCD are prescribed hydroxycarbamide therapy, but due to concerns regarding teratogenicity, patients are counselled to cease treatment prior to conception. USA registry studies suggest that hydroxycarbamide use during conception alone is not associated with adverse maternal or fetal outcomes, whereas when used throughout pregnancy it is associated with increased rates of miscarriage, still birth and low birth weight. Aims: In this study we aimed to examine the pregnancy outcomes and frequency of sickle cell related complications in patients taking hydroxycarbamide pre-conception. Methods: A single-centre retrospective study of women with SCD receiving hydroxycarbamide between July 2011 and July 2020. Data were collected on patient demographics, hydroxycarbamide use, disease activity, hospital admission and maternal and fetal outcomes. Results: 13 women (mean age 26 years, SD 5.74, range 19-40) had 17 pregnancies on hydroxycarbamide pre-conception. All patients were HbSS. Of 17 pregnancies, 15 resulted in live births, with one miscarriage and one elective termination of pregnancy for non-medical reasons. Mean gestation at delivery was 36.2 weeks. No congenital anomalies were noted. Hydroxycarbamide was stopped prior to conception in 35.3%, the remainder stopping early in the first trimester. No patients recommenced hydroxycarbamide during pregnancy or whilst breastfeeding. Three patients were switched to an exchange blood transfusion (EBT) programme in the first half of pregnancy. VOC complicated 78.6% of pregnancies antenatally and 50% postnatally; 80% of these women had more than one VOC during pregnancy. Hospital admission was required in 85.7% of patients, 21.4% needed admission to critical care. Blood transfusions were necessary in 78.6%. Postnatally, maternal complications occurred in 71.4%; the commonest causes were VOC and infection. Summary/Conclusion: Whilst our data does not alter the advice to discontinue hydroxycarbamide three months before trying to conceive, it contributes to the growing body of evidence supporting the argument that taking hydroxycarbamide at the time of conception does not result in adverse fetal outcomes. Our data highlights that for many women entering pregnancy with severe SCD, stopping hydroxycarbamide is associated with high risk of crises and hospitalisation and raises the question whether this group of women should be switched to a regular transfusion programme during pregnancy. Though our numbers are too small to support this argument, larger studies such as the TAPS-2 trial are evaluating the use of prophylactic EBT during pregnancy. In women in whom blood transfusion is associated with high risk, cessation of hydroxycarbamide leaves them with limited options. Our data adds to the small body of evidence that in this minority of cases where transfusion is not feasible, in women with severe SCD phenotype, hydroxycarbamide can be considered during pregnancy on a case-by-case basis after multi-disciplinary discussion regarding the risks and benefits with the patient, haematologist and obstetrician. Keywords: Pregnancy, Hydroxyurea, Sickle cell disease